The current research was undertaken to investigate the effect of fixed oils of Linum usitatissimum (flaxseed), Sesamum indicum L. (Sesame), and Salvia hispanical L. (Chia) seeds on the chemical profile and weight of the peritoneal fat of rats fed normal (10%fat) or high‐fat diet (HFD)(20%fat). Additionally, to analyze the phytoconstituents of these fixed oils. Gas chromatography‐mass spectrometry (GC/MS) was applied to analyze the experimental oils and the peritoneal fats. Our results revealed a remarkable effect of the experimental oils on the fatty acid profile of peritoneal fat in groups fed on HFD, they limited the increase in saturated fatty acids. Moreover, adding these oils to HFD limited the increase in body weight and decreased the percentage of peritoneal fat. In addition, oleic acid was the major fatty acid in sesame and flaxseed oils (44.2% and 33.69%, respectively). While linolenic acid was represented as a major fatty acid in chia oil (50.69%). So, we can conclude that sesame, flaxseed, and chia oils can be used as a healthy oil source in food due to their nutritional benefits and remarkable role in controlling the adverse effect of HFD on the quantity and quality of peritoneal fat.